Ozone (O3) is a gas with strong oxidation properties that has been used in many applications including the pool and spa industry as well as treating water in water storage tanks since the early 1900's. Ozone is typically produced by high-intensity ultraviolet (UV) light or by a high-voltage electric field. The normal byproduct of ozone is oxygen (O2). Ozone is created when either UV light or a corona discharge (CD) is applied to oxygen. The oxygen disassociates into single oxygen atoms which recombine into ozone. Ozone has a half life of about 2 to 12 hours in air and about 20 minutes when dissolved in water. Ozone is 13 times more soluble in water than oxygen. Ozone oxidizes and disinfects and deodorizes. Ozone also micro-flocculates iron and manganese and kills bacteria 3,000 times faster than chlorine, kills viruses, algae spores, and some parasites, precipitates heavy metals, controls formation of scales, and oxidizes oils.
Ozone is typically introduced into water to be treated by simply bubbling ozone and air into a tank of water with the use of a diffuser stone (known as an ozone aeration system) or by a venturi eductor used in conjunction with a water pump. Passing water through a venturi eductor creates a suction which draws in ozone and mixes the ozone gas with water. The ozone gas is typically introduced into a contact tank from which undissolved ozone gas is vented, or it is introduced directly into a storage tank and bubbles up through the tank and out the top of the tank. This same type of system has been used to inject ozone into water in swimming pools and spas. In some cases, spa systems have used existing “spa hydrotherapy jets” as the means to “suck in” the ozone gas and mix the gas with the spa water.
Ozone is used in combination with various chemicals in the pool and spa industry. Ozone is also used to treat iron, manganese, and hydrogen sulfide in well water and to kill pathogens in surface waters such as lakes and streams. Ozone systems come in many varieties and ozone is produced in many ways known in the art.
Ozone water treatment systems for water storage tanks are designed to clean “raw” water, e.g., well water, whereas systems for pools and spas are designed to keep treated water clean as it is used over and over again. Prior art ozone aeration systems typically include a filter to remove impurities in a reservoir of water. One prior art system teaches a water purification apparatus suspended inside a water tank. The apparatus includes a filter for filtering the water and a lift tube containing ozonated air bubbles to add ozone to the water in the tank. Such a prior art system is disclosed in U.S. Pat. No. 5,190,648 to Ramsauer, issued Mar. 2, 1993.
In the Ramsauer system, air containing ozone generated by an ozone generator is injected into the bottom of the lift tube using a diffuser, which causes the ozonated air to be converted into bubbles. The ozonated air bubbles up through the water in the lift tube and into the water tank. Excess ozonated air escapes through the top of the tank. As taught in Ramsauer, the lift tube is part of an in-the-tank filter module. The ozone gas mixing and filtration and circulation of the water are accomplished within the filter module assembly. The action of the bubbles rising and expanding in the lift tube causes a current flow, which causes the water to be drawn through the filter where the water is filtered with each pass to thereby filter the water prior to its contact with the ozonated air.
Prior art ozone water treatment systems are generally simple to install since they are positioned inside the fluid reservoir and therefore require no cutting into the wall of reservoir, whether it be a pool, spa, or tank, to install separate lines. However, such a “single” reservoir fluid treatment system is more difficult to maintain, because the filter needs to be pulled from the reservoir for cleaning and maintenance. In addition, the Ramsauer system, for example, does not treat the excess ozonated air bubbles emanating from the fluid in the reservoir after treatment, for destruction or to channel it elsewhere for some other use. There is no mechanism for preventing the pool or spa user from being exposed to this ozonated air bubbling off the surface of the water, and thus having to suffer the damaging effects of ozone on the user's mucus membranes, eyes, and skin.